ES3037042T3 - Tourniquet - Google Patents

Abstract

A tourniquet for victims of wounds of varying sizes comprises a strap that is wrapped around the injured limb to provide the desired hemorrhage-suppression force, configured with first and second sections of different widths. In one embodiment, the gas flow control assembly of a pneumatic tourniquet comprises a housing containing a longitudinally displaceable force-transmitting element and a gas cartridge; and a pivoting activation handle. By pivoting about its axis of rotation, pressurized gas is discharged from the gas cartridge and flows into an inflatable strap to provide the hemorrhage-suppression force. In other embodiments, the pneumatic tourniquet comprises one or more flow control units, a manual pressure-release initiator, a connecting section to mitigate puncture, and a strap configured with an interconnected inner, outer, and intermediate sealant layer.

Description

DESCRIPTION

Tourniquet

Field of Invention

The present invention relates to the field of inflatable tourniquets. In some embodiments, the invention relates to a pneumatic inflatable tourniquet for hemorrhage control that is adapted for use by both a paramedic and inexperienced personnel unexpectedly found in a prehospital emergency setting.

Background of the Invention

A tourniquet is a well-known device for stopping or halting bleeding. Traditionally, a strip of material, such as a bandage, is twisted with an improvised instrument like a stick to apply pressure to an artery and thus stop the flow of blood through a limb.

An online brochure on the Delfi Medical elastic cuff (at http://www.delfimedical.com/wpcontent/uploads/2013/10/EasifitCuffBrochure-Sept2013.pdf) describes cylindrical, variable-contour tourniquet cuffs. These cuffs are designed for use by victims with wounds of varying sizes and include a strap that can be wrapped around the injured limb to provide the desired hemorrhage suppression or interruption force. The cuff is configured with a first and second section of different widths. The second section (i.e., the port) is a circumferential pressure-applying section that is narrower and longer than the first section and is designed to wrap around the injured limb to apply circumferential pressure and suppress or interrupt bleeding.

M.A.S. MED Global Ltd.'s WO 2014/191987A1 document describes a pneumatic tourniquet comprising an inflatable strap, a compressed gas container, and a flow control unit attached to the inflatable strap. When activated, the flow control unit is configured to selectively deliver a dose of pressurized gas discharged from the gas container or canister into an internal strap cavity to achieve a predetermined cavity pressure for applying the required hemorrhage suppression or interruption force to a limb.

As described in the document: "Tourniquet pain in a volunteer study: effect of changes in cuff width and pressure", J.P Estebe et al., Anesthesia, January 2000; 55(1):21-6, a study found that a wide tourniquet cuff is less painful than a narrow cuff if inflated to lower pressures and at these lower pressures is still effective in occluding blood flow.

US patent 8,568,441B2 from Western Clinical Engineering describes methods for manufacturing and inflating an elongated tourniquet cuff bladder that can be secured around a patient's limb. The method includes sealing together the lateral edges of the material layers to form the bladder, and hardening the cuff with a hardener to compress the portion of the bladder beneath the hardener inward toward the limb, while preventing two cuff layers from contacting each other at a location adjacent to a cuff edge. This provides a continuous pneumatic passage in the bladder between the overlying hardener and the sealed edge to distribute the inflation gas through the passage along the length of the bladder.

US patent 6,682,547B2 by McEwen et al. describes a tourniquet cuff with an identifying apparatus that includes an outer strip; an inner strip positioned against the outer strip; a hermetic seal joining the inner strip to the outer strip to form a cuff having a physical feature in which the cuff includes an inflatable bladder of a predetermined length greater than the circumference of a limb at a selected location; and a cuff connector positioned on the cuff and pneumatically communicating with the bladder to releasably connect to a tourniquet instrument to establish a gas-tight passage between the bladder and the instrument.

Searle et al.'s WO 2014/023960A1 describes an automated pressure regulator that can be integrated into a portable battlefield tourniquet. The automated pressure regulator includes an inlet port configured to connect to a pressurized gas cylinder to receive pressurized gas from it, and an outlet port that is sealed to an inflatable bladder. The automated pressure regulator is applicable to devices where rapid inflation is important and where monitoring the pressure in the internal bladder is desirable to maintain an acceptable (minimum) pressure, but where user observation is not necessarily practical due to surrounding environmental conditions.

US patent 2015/0230803A1 by Hill Schreckengaust et al. describes a tourniquet system for the rapid, automatic application of appropriate pressure to stop bleeding from an injured limb while minimizing tissue damage due to excessive pressure. Pressure is applied to the limb by inflating a tourniquet cuff with compressed gas. The invention also relates to a method for controlling bleeding from a limb using the tourniquet system.

Jordanian patent US 2,839,062 describes a pneumatic tourniquet end for restricting blood flow to extremities. More specifically, this patent describes an inflatable, portable, and lightweight tourniquet with an independent source of pneumatic pressure, designed for easy self-application.

US patent 2007/0191881A1 by Amisar et al. describes a self-regulating tourniquet comprising a pressure source, a pressure applicator associated with the pressure source and operative for applying pressure therefrom to a limb, and a pressure regulator associated with the pressure source and the pressure applicator operative for restricting the pressure transferred from the pressure source to the limb to a designated maximum pressure applied to the limb. The pressure source and the pressure applicator may be separate modules adapted to be coupled by means of a connector to establish the passage of gas from the pressure source to the pressure applicator.

Hazlewood's US patent 3,670,735 describes a disposable plastic tourniquet that includes an elongated inflatable wrap formed from three layers of vinyl plastic, one layer of which extends from one end of the wrap to form a long tab. A sheet of reinforcing material is placed between two of the vinyl layers to increase the contact surface, and a strip of pressure-sensitive tape extends from each side of the wrap to engage the tongue and secure the tourniquet in position on the patient.

US patent 2003/139766A1 by McEwen et al. describes a pneumatic tourniquet adapted for self-application by an injured person in a military or emergency situation to stop arterial blood loss in an injured arm or leg. The tourniquet includes a bladder having a width and length dimension greater than the circumference of an injured limb at a selected location; and a clamping means for securing the bladder around the limb at the selected location and adapted to seal the bladder across its width, establishing an inflatable portion of the bladder that surrounds the injured limb at the selected location.

Other manually applied tourniquets that use a force applicator such as a ratchet or winch are capable of stopping blood loss from an injured arm within 20 to 80 seconds. However, a significantly greater force, on the order of 300 to 600 N, must be applied for a significantly longer time to suppress or stop bleeding from the femoral artery. This is due to its greater depth relative to the skin surface compared to the brachial artery, and to the larger dimensions of the thigh relative to the arm. The actual force required to suppress or stop bleeding depends on the thickness of the limb, the depth of the artery within the limb, and the width of the strap transmitting the applied force to the injured artery. The width of the strap is generally limited to reduce the magnitude of the manually applied force needed to suppress or stop bleeding. In particular, due to the narrow dimension of the strap of approximately 2.5 cm which cuts the skin if excessive force is applied, damage to the soft tissues, muscles, nerves and bones of the injured limb may occur.

It would be desirable to provide a pneumatically applied tourniquet that has a relatively wide strap that is capable of applying uniform pressure over an injured limb despite the sufficiently high hemorrhage suppression or interruption force applied by it and that is therefore not painful to the soft tissue.

Pneumatic tourniquets are commonly used in limb surgery to achieve near-bloodless surgery while still applying a relatively high hemorrhage-stopping force to an injured limb. These prior art pneumatic tourniquets comprise an inflatable cuff, which is a type of strap configured with a rubber bladder encased in a plastic or fabric cover. A connecting tube links the cuff to a pressure device that includes an air compressor, pressure setting buttons, a digital display of the pressure setting, and a timer. The pressure device is electrically powered and therefore plugs into a wall outlet. The apparatus associated with these prior art pneumatic tourniquets is thus stationary and not useful for clinicians who need to treat injured victims in remote locations. Furthermore, the wide straps used in hospitals, which can be on the order of 20 cm wide, are bulky and cannot be easily transported in a compact bag for convenient use by clinicians.

The disadvantages of other prior art pneumatic tourniquets include the lack of protection of the pressurized gas source needed to inflate a strap and, therefore, the lack of suitability for use in a battlefield environment and the inability to use the pressurized gas source for more than one hemorrhage suppression or interruption operation.

Injured victims are prone to limb tissue ischemia during prolonged tourniquet use, resulting from the cessation of blood flow distal to the tourniquet. The severity of ischemic changes depends on the length of time the limb has been obstructed. These symptoms may be reversible if the tourniquet pressure is maintained for a short period of less than two hours, or if it is released periodically for short intervals of a few minutes, allowing some bleeding to reappear. However, clinicians are advised against releasing pressure before transporting the victim to a hospital—for example, by deflating the strap if using a pneumatic tourniquet—due to the possibility of progressive exsanguination, which can lead to death. After deflating a pneumatic tourniquet, the products of acidosis, lactate, toxic metabolites, and oxygen free radicals are introduced into the bloodstream and cause complications such as systemic metabolic changes and reperfusion syndrome that can lead to cardiac arrest.

Furthermore, if a pneumatic tourniquet were to temporarily deflate in a prehospital setting, the stored pressurized gas would be depleted while the inside of the strap is exposed to atmospheric air, and therefore the pneumatic tourniquet could not be used after deflation.

An object of the present invention is to provide a pneumatic tourniquet for use by both a physician and inexperienced personnel in an emergency prehospital setting, for the purpose of inflating a strap by applying a hemorrhage suppression or interruption force at a predetermined pressure.

An additional object of the present invention is to provide a pneumatic tourniquet that is not harmful to injured victims, both adult and pediatric, while the inflated strap is being applied.

An additional object of the present invention is to provide a compact, reliable, and easy-to-use pneumatic turnstile that can be readily deployed in remote locations.

An additional object of the present invention is to provide a pneumatic tourniquet that is adapted to be used by a physician to temporarily deflate the strap, if necessary.

An additional object of the present invention is to provide a pneumatic tourniquet having a flow control unit that can be used for a plurality of hemorrhage suppression or interruption operations.

An additional object of the present invention is to provide a pneumatic tourniquet that reduces the consumption of pressurized gas used for each hemorrhage suppression or interruption operation.

Other objects and advantages of the invention will become apparent as the description progresses.

The invention is limited to the subject matter defined in the claims. Other aspects described are included for illustrative purposes only.

Summary of the Invention

According to the present invention, a pneumatic tourniquet is provided as set forth in claim 1 below. The tourniquet can be used for victims with wounds of different sizes.

In one embodiment, the pneumatic tourniquet further comprises a constriction device adapted to receive a free end of the strap, such that the free end can move freely within the constriction device until it is secured therein when the strap is sufficiently taut to transmit the force for suppressing or interrupting bleeding. The constriction device may comprise a housing member and a rocker arm rotatably mounted on and within the housing member by means of a longitudinally extending shaft. The rocker arm is configured to move angularly about the shaft until a surface of the rocker arm is established in a clamping relationship with a fixing edge of the housing member while the strap is interposed between the rocker arm surface and the fixing edge, in response to a force applied by the injured limb on the rocker arm when the strap is sufficiently taut.

In one aspect, the pneumatic tourniquet further comprises a sealing element, wherein a clamping force applied by said rocker surface and said fixing edge on said sealing element prevents the flow of pressurized gas from a pressure-applying section of said strap that is wrapped around the injured limb to said free end, thereby allowing said free end of the strap to be considerably thinner than said pressure-applying section.

In one aspect, the sealing element is provided internally within the belt, the belt being configured with an inner layer, an outer layer and an intermediate sealing layer that are interconnected.

In one respect, the sealing element is external to the strap.

A user-friendly gas flow control assembly for a pneumatic tourniquet comprises a housing containing a recess for attaching a gas cartridge filled with pressurized gas and normally sealed by an occlusion element, a longitudinally displaceable force-transmitting element, and an outlet port; a pivoting actuation handle configured with a broad, substantially flat, user-manipulating surface; and a structure provided with said housing that cooperates with said actuation handle to define an axis of rotation of said actuation handle, wherein, by pivoting said actuation handle about its axis of rotation, an actuation force is transmitted that impetuously contacts said force-transmitting element to forcefully contact and open at least a portion of said occlusion element, causing the pressurized gas to be discharged from said gas cartridge and flow through said outlet port into an inflatable strap that can be wrapped around an injured limb to provide the desired force to suppress or interrupt bleeding.

In one respect, the occluding element is a perforable cover and the force transmission element is a puncture pin that ends with a pointed end that can be moved to an inwardly offset position where the pointed end pierces the perforable cover.

In one aspect, the force transmission element is an actuating piston configured to cooperate with a valve stem associated with the gas cartridge.

In one aspect, the housing-equipped structure that cooperates with the actuating handle to define the axis of rotation is a laterally extending bar rotatably mounted in corresponding seats provided with the housing to define the axis of rotation of the actuating handle. A cam fixed to the bar may be within manageable proximity to the force-transmitting element.

A flow control unit (such as a pressure regulating unit) comprising a housing member configured with an inlet for receiving pressurized gas on demand and with an internal cavity; a hollow tube with an outside diameter of less than 2.5 mm that is in fluid communication with said inlet; a piston with an intermediate orifice connected to said tube and with an outside diameter significantly larger than said tube, said piston being axially displaceable and leak-proof within said internal cavity to define at its distal end a supply chamber in fluid communication with atmospheric air and, at its proximal end, a regulating chamber that is in fluid communication with said inlet through said tube; and a fixed sealing element, wherein, after the flow of pressurized gas into said regulating chamber, said piston is displaced distally by a pressure differential between the pressure in said regulating chamber and in said supply chamber until a distal end of said tube is occluded by said sealing element, to prevent further entry of pressurized gas.

A pneumatic tourniquet comprises an inflatable strap that is wrapped around an injured limb to provide a desired hemorrhage-suppressing force; and a pressure-regulating unit configured with an inlet for receiving pressurized gas on demand; an axially displaceable piston sealed within an internal cavity to define at a distal end thereof a supply chamber in fluid communication with atmospheric air and, at a proximal end thereof, a regulating chamber that is in fluid communication with said inlet and with an interior of said strap; and a manual pressure-release initiator, which, when displaced, provides a clearance that is in fluid communication with said regulating chamber and with atmospheric air to selectively reduce the fluid pressure within the interior of said strap while preventing further entry of pressurized gas into said regulating chamber.

A perforation mitigation connection section for connecting an inflatable belt to a gas flow control assembly housing comprises a flexible inlet port protruding through an outer layer of an inflatable belt and having a central passageway in fluid communication with an interior of the belt, wherein said inlet port is coupled with a discharge port of a gas flow control assembly through which pressurized gas can be discharged to inflate the belt; and a plurality of fastening means protruding from the outer layer of the belt and separate from said inlet port, wherein each of said fastening means is coupled with a corresponding fixed element associated with a housing of the gas flow control assembly.

In one aspect, the plurality of fastening means is integrally formed with a rigid plate positioned inside the belt and attached to the outer belt layer and formed with an opening through which the inlet port protrudes.

In one aspect, the rigid plate is attached to a semi-rigid sealing layer adapted to provide additional protection against discharge of pressurized gas from the connection section, and an inlet port mounting element is attached to said semi-rigid sealing layer.

As mentioned in this document, "longitudinally" means along a direction parallel to the axis of a tubular gas cartridge when coupled with the puncture unit housing. "Lateral" means in a direction substantially perpendicular to the longitudinal direction. "Transverse" means in a direction at an angle to the longitudinal direction that is not necessarily the lateral direction. "Proximal" means in the direction toward a user-accessible element of the tourniquet, such as the manual pressure-release initiator or an unfixed edge of the trigger handle distant from its axis of rotation. "Distal" means in a direction opposite to the proximal direction. Other directional terms, such as "up," "over," and "under," refer to an orientation when the tourniquet is positioned on a horizontal surface, although the tourniquet may be positioned in any other desired orientation.

Brief description of the drawings

In the drawings:

- Figure 1 is a perspective view from the top of an embodiment of a pneumatic tourniquet, shown when the constricting device is in an open position and the inflatable strap is only partially illustrated;

- Figure 2 is an exploded view of the turnstile in Figure 1;

- Figure 3 is a perspective view from the top of an inflatable strap that can be used in conjunction with the tourniquet of Figure 1, shown in a flattened condition;

- Figure 4 is a perspective view from the top of the tourniquet in Figure 1, shown when the constriction device is in an open position and the inflatable strap is removed;

- Figure 5 is a perspective view from the bottom of the tourniquet in Figure 1, shown when the constriction device is in a closed pivot position and the inflatable strap is removed;

- Figure 6 is a perspective view from the top of the tourniquet in Figure 1, shown when the upper housing of the gas flow control assembly is removed and the gas cartridge is partially removed to illustrate the fastening devices that connect the inflatable strap to the lower housing;

- Figure 7 is a cross-sectional view of the tourniquet of Figure 1 when deployed during a hemorrhage suppression or interruption operation, cut along a medial plane through the gas flow control assembly, two separate portions of the strap when inflated and the injured limb;

- Figure 8 is a cross-sectional view of an injured limb cut along a frontal plane, showing the tourniquet of Figure 1 when deployed during a hemorrhage suppression or interruption operation such that the inflated strap is wrapped around the limb and secured in a clamping relationship with respect to the constricting device;

- Figure 9 is a cross-sectional view of a constriction device used in conjunction with the tourniquet of Figure 1, showing an inflatable strap being inserted through it;

- Figure 10 is a plan view of the components associated with the gas flow control assembly, as shown when removed from the housing;

- Figure 11 is a cross-sectional view of the components of Figure 10, cut along a horizontal plane;

- Figure 12 is a horizontal cross-sectional view of another embodiment of a gas flow control assembly, shown without the pressure regulating unit tube;

- Figure 13 is a perspective view from the top of an actuating handle when separated from the housing of the gas flow control assembly used in conjunction with the tourniquet of Figure 1;

- Figure 14 is a perspective view from the top of the turnstile in Figure 1, shown when the trigger handle is in a pivoting position;

- Figure 15 is a longitudinal cross-sectional view of a portion of the gas flow control assembly used in conjunction with the tourniquet of Figure 1, showing the actuating handle in a non-pivoted position while a cam associated therewith is in actuatable proximity to a punch pin head element;

- Figure 16 is a longitudinal cross-sectional view of a portion of the gas flow control assembly used in conjunction with the tourniquet of Figure 1, showing the trigger handle in a pivoting position;

- Figure 17 is an enlargement of a part of Figure 11, showing details of the pressure regulating unit;

- Figure 18 is a perspective view from the front of a usable tube together with the pressure regulating unit of Figure 17;

- Figure 19 is a longitudinal cross-sectional view of a portion of the gas flow control assembly used in conjunction with the tourniquet of Figure 1, showing the manual pressure release initiator when set in a retracted proximal position;

- Figure 20 is a longitudinal cross-sectional view of a portion of the gas flow control assembly used in conjunction with the tourniquet of Figure 1, showing the manual pressure release initiator when set in an advanced distal position;

- Figure 21 is a perspective view from the top of another embodiment of a pneumatic tourniquet, shown when deployed over a schematically illustrated injured limb and the constriction device is coupled with the gas flow control assembly;

- Figure 22 is a perspective view from the top of the tourniquet of Figure 21, shown when deployed over an injured limb schematically illustrated and the constriction device is separated from the gas flow control assembly;

- Figure 23 is a perspective view from the top of another embodiment of a pneumatic tourniquet, shown when deployed over a schematically illustrated injured limb and the constriction device is coupled with the gas flow control assembly;

- Figure 24 is a side perspective view of another embodiment of a pre-fed pneumatic turnstile with an inflatable belt;

- Figure 25 is a top view of the turnstile of Figure 24, shown when an upper housing is removed from the gas flow control assembly;

- Figure 26 is a perspective view from the top of a portion of an inflatable strap used in conjunction with the tourniquet of Figure 24;

- Figure 27A is a top view of the entire strap of Figure 26, shown in a flattened condition;

- Figure 27B is a side view of the strap in Figure 27A, when inflated;

- Figure 27C is a perspective view of the belt of Figure 27A when it is connected to the gas flow control assembly and its free end is inserted through the constriction device; - Figure 28A is a cross-sectional view of the wide-width connection section of Figure 26;

- Figure 28B is an exploded perspective view of the components used to produce the connection section of Figure 28A;

- Figure 28C is a perspective view of the components of Figure 28B, when they are joined together;

- Figure 28D is an exploded perspective view of the attached components of Figure 28C when placed in underlying relation to an external surface of an inflatable belt, prior to their attachment to it;

- Figure 29 is a perspective view from the side of the gas flow control assembly of Figure 24 when it is separated from the constriction device and the trigger handle is set in a pivoting position;

- Figure 30 is a cross-sectional view of the gas flow control assembly of Figure 24, when the trigger handle is in a non-pivoted position and the trigger piston is set to an unactivated position;

- Figure 31 is a cross-sectional view of the gas flow control assembly of Figure 24, when the trigger handle is in a pivoting position and the trigger piston is set in an activated position;

- Figure 32A is a cross-sectional view of a portion of the constriction device of Figure 24, showing the rocker arm in a non-pivoted position;

- Figure 32B is a cross-sectional view of the turnstile of Figure 24, showing the rocker arm in a pivoting position and the strap extending circumferentially outside the gas flow control assembly and the constricting device in a perspective view to illustrate the weld lines;

- Figure 33 is a perspective view from the side and bottom of the tourniquet of Figure 24 when the strap is removed, showing one embodiment of the constriction device;

- Figure 34 is a perspective view from the side of the tourniquet of Figure 24 when the strap is removed, showing another embodiment of the constricting device; and

- Figure 35 is a perspective view from the side and bottom of the tourniquet in Figure 24 when the strap is removed, showing another embodiment of the constriction device.

Detailed description of the invention

The compact pneumatic tourniquet of the present invention is used primarily, but not necessarily, in emergency situations, such as after a car accident, an explosion, a stabbing incident, or on the battlefield in an attempt to stop bleeding from the extremities and prevent death due to blood loss. Circumferential pressure is applied around a part or portion of the injured limb after the strap is inflated to a predetermined pressure, causing the blood vessels to which the pressure is applied to become temporarily occluded.

Due to its user-friendly configuration, the tourniquet is easily activated by all users, including paramedics, inexperienced personnel unexpectedly located in an emergency environment, and even the injured victim, to initiate an operation to suppress or interrupt bleeding, and the strap is easily wrapped around the injured limb and tightened.

The tourniquet's unique configuration, as described later, dramatically reduces the complications normally associated with prolonged tourniquet use and injuries to the skin and subcutaneous tissues as a result of excessive pressure applied to pediatric victims.

Since the pressurized gas for use in the pneumatic tourniquet is supplied internally within the housing of a gas flow control assembly, generally by means of a gas cartridge, and not externally to the housing by means of an electrically operated gas transfer unit as practiced in the prior art, the compact tourniquet of the present invention is free of electrical or electronic components and can be advantageously used in wet or muddy environments. Of course, in some embodiments, a well-sealed electronic module can be added, such as one comprising a GPS component for locating a subject or sensors for determining some of the subject's physiological characteristics in real time, similar to an electronic module provided to a diver.

Figures 1 and 2 illustrate an embodiment of the pneumatic tourniquet 40. The pneumatic tourniquet 40 comprises a gas flow control assembly 43, a constriction device 48 pivotally connected to the gas flow control assembly 43, and an inflatable strap 49 that is connected to the gas flow control assembly 43 and selectively clamped by the constriction device 48.

The inflatable strap 49 can be configured with three layers 13-15 of substantially equal lengths and widths. The inner layer 15 is made of a flexible, tear-resistant material. The outer layer 13, exposed to the underlying ground, which often contains sharp objects such as thorns and broken glass, is made of a flexible, puncture-resistant material, such as silicone elastomer or a flexible fabric, such as nylon or polyester, and sealed with a layer of puncture-resistant material, such as polyurethane. The middle layer 14 is made of a sealant, such as polyurethane.

The gas flow control assembly 43 is configured with a housing, for example, a housing having an upper section 2 and a lower section 38 as illustrated, to form a user-accessible, curved proximal surface. The upper housing section 2 and the lower housing section 38 can be coupled together by a plurality of spaced fastening devices 9, for example, threaded fasteners. Two longitudinally spaced arms 51 and 52 can extend downward from the same side of the lower housing section 38, each terminating in a corresponding arched protruding seat 54. The two seats 54 face each other.

The gas flow control assembly 43 comprises a replaceable gas cartridge 21, a puncture unit housing 18 within which a metal cover 21, normally sealing the gas cartridge, is perforated to allow pressurized gas, such as carbon dioxide or nitrogen, to be discharged from the gas cartridge, a pressure regulator unit 24 to control the pressure of the discharged gas inside the inflatable strap 49, and a manual pressure release initiator 4 operatively connected to the pressure regulator unit 24 to selectively deflate the strap 49 while ensuring that the remaining pressurized gas inside the gas cartridge 51 is not discharged. The manual pressure release initiator 4 may protrude from the curved proximal surface of the housing.

The gas cartridge 21 can be supplied with carbon dioxide, nitrogen, a noble gas, or a refrigerant gas. The gas, which is compressed to a pressure of 70 to 170 bar at 60 °C and approximately 20 bar at -10 °C, can be replaced by removing the cartridge cover 5. The cover 5 can have, for example, a width of approximately half the width of the housing, a length of approximately one-quarter the length of the housing, and a height approximately equal to the total thickness of the upper housing section 2 and the lower housing section 38, or any other suitable dimension. The cartridge cover 5 can be releasably secured to the housing by means of one or more magnets 6, which are attached to the lower housing section 38.

Alternatively, the gas flow control assembly 43 can be configured without a pressure regulator unit or without a puncture unit housing. When the gas flow control assembly is configured without a puncture unit housing, another type of force-transmitting element, such as element 472 shown in Figure 30, can be selectively driven to forcefully contact and open at least a portion of an occlusion element that normally seals the gas cartridge 21, to facilitate the flow of pressurized gas from the gas cartridge and into the inflatable strap 49.

Alternatively, the gas flow control assembly is provided with a non-replaceable gas cartridge and, consequently, is configured without a cartridge cover.

A thin, wide-area trigger handle 3 for initiating inflation of the strap 49 is pivotally connected to a distal region of the gas flow control assembly housing 43. The trigger handle 3 is designed to have a wide, easy-to-use area when its width is more than 60% of the width of the gas flow control assembly 43. The trigger handle 3 typically overlaps a recess 39 formed in the upper section of the housing 2 by a small gap sufficient to insert a finger, for example, 0.5 cm, and to pivotally lift the trigger handle 3. The thickness of the trigger handle 3 is generally uniform; however, it may gradually increase, for example, from 1 mm in the finger contact area to maximize clearance, to 3 mm in the pivot axis area, thereby increasing the overall structural strength of the trigger handle. The activation handle 3 is substantially flat to reduce the amount of material required, although it may be somewhat curved, while exhibiting substantially high structural strength to be able to transmit an activation force, as will be described later.

In one embodiment, the recess 39 extends distally to the timing device 34, for example a digital timing device, adapted to indicate the start of a hemorrhage suppression or interruption operation, which is housed in the half of the upper housing section 2 not occupied by the cartridge cover 5 that is distal to the curved proximal surface.

The constriction device 48 for holding the inflatable strap 49 when sufficiently tensioned comprises a housing member 10 and a rocker arm 11 rotatably mounted on, and within, the housing member 10 by means of the shaft 12.

The housing member 10 has a thickened end wall 56, which may be flat and rectangular, and an outer wall 58 and two longitudinally spaced side walls 57 extending downward from the top wall 56 to a height below the lower surface of the end wall 56 to define a projecting portion 59, with respect to the illustrated orientation. The lower edge 66 of the outer wall 58 forms a fixing edge. An opening 62 is formed in each side wall 57, such that the two openings 62 are aligned. A curved element 64 extends downward from the inner edge 63 of the top wall 56 and terminates with two longitudinally extending hinge elements 67 that are received in corresponding seats 54, allowing the housing member 10 to rotate about the axis coinciding with the seats 54.

The rocker arm 11 has a flat surface 71, which may be rectangular, and two longitudinally spaced side walls 74 extending upwards from the surface 71 and which may be curved upwards. Each side wall 74 may have a short portion 77 projecting laterally from the curved portion and whose upper edge is coplanar with the surface 71. The inner short legs 81 and outer short legs 83 extending longitudinally between the two side walls 74 may extend downwards from the surface 71. The longitudinal spacing between the side walls 74 is less than that of the side walls 57 of the housing element 10. An opening 76 is perforated in each side wall 74, preferably in a region closer to the corresponding short portion 77, so that the two openings 76 are aligned. The shaft 12 is adapted to be received within the openings 62 and 76, to allow the rocker arm 11 to oscillate around it. An outer wall 79, i.e., oriented in the opposite direction to the arms 51 and 52, extends longitudinally between the two short portions 77 and extends upward from the surface 71 to a height significantly less than that of the side walls 74.

Figure 3 illustrates a top view of the inflatable strap 49 when flattened. The strap 49 can be configured with two integral sections 44 and 46 of different widths. Section 44, with a uniform width A (e.g., 50 mm), is elongated and adapted to be wrapped around an injured limb to apply circumferential pressure and suppress or stop bleeding. Section 46, with a maximum width B greater than width A (e.g., 100 mm), which can be connected to the housing of the gas flow control assembly to increase the strength of the connection, can be configured with a curved periphery (e.g., elliptical). By providing a strap with a relatively narrow pressure-applying section, the constricting device through which the strap 49 can move freely until it is restricted can also be advantageously narrow, resulting in a compact device. The short terminal end 45 of the belt 45, which is opposite the connecting section 46, which is included in the free end of the belt being pulled during a tensioning operation, may have a width slightly larger than A, for example 60 mm, to prevent the free end from retracting in an opposite direction through the constricting device.

Unlike manually applied tourniquets, which are narrow and typically have a strap width of up to 5 cm due to the difficulty of applying the required hemorrhage-stopping force, the pneumatic tourniquet of the present invention is capable of achieving sufficiently high pressures to apply hemorrhage-stopping force even to limbs of very large diameter. A strap 49 configured with two integral sections 44 and 46 of different widths has significant clinical advantages, as the hemorrhage-stopping force will not be transmitted entirely through the relatively narrow section 44. Wrapping a relatively wide strap section 46, for example, 15 cm, around the limb, or at least most of the limb, leads to a uniform distribution of the applied pressure over the limb surface and helps to reduce pain and local damage—advantages that are particularly important for subjects with small limb diameters, such as pediatric patients. At the same time, a relatively high hemorrhage-suppressing force can be transmitted through a relatively long and narrow section 44 to adult victims who have relatively large diameter limbs without undue pain or tissue damage.

In one embodiment, the two sections 44 and 46 are made of different materials with varying degrees of flexibility. The relative width of sections 44 and 46 may change accordingly after inflating the belt 49. For example, sections 44 and 46 may have the same width before inflation; however, after inflation, section 44 becomes thinner and longer than section 46.

It will be noted that an inflatable strap can have a uniform width.

In one embodiment, the strap provided with sections 44 and 46 of different widths may be non-inflatable. Sections 44 and 46 may be integrally formed with the non-inflatable strap, or alternatively, they may be connected to each other, for example, in a releasable manner, by various means well known to those skilled in the art, such as adhesives, sewing, fusing, buttons, and hook-and-loop fasteners.

The connection section 46, as shown in Figure 7, is internally provided with a relatively rigid coupling plate 61 adapted for attachment to the housing of the gas flow control assembly, in addition to the outer layer 13, the intermediate sealing layer 14, and the inner layer 15 of the inflatable belt. The inner layer 15 is adapted to be in contact with a wound end 35. The internal coupling plate 61, which can be made of a relatively rigid plastic such as polypropylene or high-density polyethylene, is connected between the outer layer 13 and the sealing layer 14, for example, by welding. The three layers 13 to 15 can be welded together by a weld line 17 that extends longitudinally along the entire corresponding edge across the width of the inflatable belt, encompassing both the pressure application section 44 and the connection section 46.

As further shown in Figure 3, a plurality of separate snap fasteners or clamping devices 65, or any other suitable type of fastening device such as screws or clips, connected to the coupling plate, project outward into the connection section 46 from the outer belt layer. Also projecting outward from the outer belt layer is a tubular port 73 for the passage of pressurized gas into the belt, which is generally located centrally with respect to the plurality of clamping devices 65.

Figures 4 and 5 illustrate the tourniquet 40 from below when the constriction device 48 is configured in an open position suitable for assisting in a hemorrhage suppression or interruption operation and in a closed, pivoting position, respectively, suitable for compact storage in a bag in preparation for dispatch during an emergency to assist an injured victim. When the constriction device 48 is placed or set in the pivoting position, the hinge elements rotate approximately 180 degrees until the end wall 56 of the housing element is substantially parallel to the lower surface 41 of the gas flow control assembly housing 43.

When the strap is not inflatable, a small member from which arms 51 and 52 extend downwards (Figure 2) can be secured to the strap instead of the gas flow control assembly housing.

The strap 49 shown in Figure 3 can also be stored compactly, for example after being wound up on itself, in the same bag or a different one than the pivoting constriction device and gas flow control assembly.

As shown in Figures 4 and 6, the partially illustrated connection section 46 of the inflatable strap is positioned in a supporting relationship with the lower surface of the housing 41 by means of the plurality of snap fasteners or clamping devices 65, which are attached to a portion of the lower housing section 38 located below the partially illustrated gas cartridge 21, when coupled to the puncture unit housing 18.

Some elements that allow the flow of pressurized gas into the interior 53 of the inflated strap 49 are illustrated in Figures 4, 6, 7 and 17. The flow of pressurized gas discharged from the gas cartridge is directed into the interior 53 of the inflatable strap by means of the centrally perforated port 73. The port 73 may be part of an element that can be coupled, for example, in a releasable manner, with the gas flow control assembly 43 before performing a hemorrhage suppression or interruption operation. Such an element may comprise an integral support element 78 having a maximum diameter or width significantly larger than that of the port 73. The tubular port 73 may be factory secured to the coupling plate 61 through an opening formed in the coupling plate 61 and in the outer layer 13 and the middle layer 14 of the inflatable belt, such that the support member 78 is brought into pressure relationship with the coupling plate 61.

Port 73 can be coupled to the pressure regulating unit 24 via a tapered nozzle 117 extending downwards from a discharge conduit 114 of the pressure regulating unit by a simple pressure movement transmitted through the coupling section 46. When the coupling section 46 is attached to the lower surface of the housing, the pressurized gas discharged from the gas cartridge will be directed through the tube 26 of the pressure regulating unit 24, the discharge conduit 114, the nozzle 117 and port 73 into the interior 53 of the inflatable belt.

As pressurized gas is introduced into the common interior 53 of the pressure application section 44 and the coupling section 46, the inner layer 15 separates from the intermediate sealing layer 14 as pressurization increases inside interior 53.

Alternatively, connection section 452 shown in Figures 28A-D may be used.

Figure 8 illustrates the pneumatic tourniquet 40 when deployed during a hemorrhage control operation. To ensure rapid hemorrhage control, the free end 44' of the strap is pre-inserted through the constriction device 48 while the tourniquet is stored. During an emergency, the tourniquet 40 is first removed from its pouch, and the constriction device 48 is positioned on a selected region of the injured limb 35 relative to the wound site. Next, the pressure application section 44 is wrapped around the limb 35 until the connecting section 46 joins the housing of the gas flow control assembly 38 while the latter remains supported by the limb 35. By pulling freely on the free end 44' of the strap by applying a force T in a direction away from the constricting device 48, the pressure application section 44 is tightened sufficiently to allow the subsequent hemorrhage suppression or interruption operation to be performed after the discharge of pressurized gas from the gas cartridge has been initiated.

As shown in Figure 9, the strap 49 is placed in movable contact with the attachable surface 71 of the upper rocker arm 11 and under the shaft 12 as it is fed through the constriction device 48, for example, in a factory or by a physician when applying the tourniquet. When the strap 49 is sufficiently taut while wrapped around the injured limb, the limb applies a force to the inner wall 75 of each side wall of the rocker arm 11. This applied force causes the rocker arm 11 to rotate about the shaft 12, counterclockwise according to the illustrated orientation, until the outer wall 79 of the rocker arm is in clamping contact with the fixing edge 66 of the outer wall 58 of the housing member 10 while the strap 49 is interposed between the outer wall 79 of the rocker arm and the outer wall 58 of the housing member. The angular displacement of the rocker arm 11 can also be facilitated by spacing the shaft 12 from the vertical centerline of each side wall 74, to provide an eccentric movement. In this clamping relationship, the free end of the belt 49 can no longer be pulled freely, but is held in place.

The manual pressure release initiator 4, the operation of which will be described later, can be used to disengage the strap from the fixing rim 66 by reducing the pressure inside the strap and allowing the strap to move freely again, or to gradually release the pressure before removing the tourniquet.

Returning to Figure 8, the clamping relationship established between the outer wall of the rocker arm and the outer wall of the housing element also advantageously allows the free end of the strap 44' to be considerably thinner than the pressure-applying section 44 of the strap. When pressurized gas is introduced at a predetermined pressure inside the strap, the strap inflates and applies a radial hemorrhage-suppression or interruption force S to the limb 35. Without the cooperation of the constriction device 48, an inflated free end 44', which can be on the order of 30 cm long, can be cumbersome and sometimes even harmful to the injured victim and to the healthcare professional attempting to assist the victim. The outer wall of the rocker arm and the wall of the outer housing element, when a clamping relationship is established at the fixing edge, both apply a clamping force to the intermediate sealing layer of the belt, thereby preventing the passage of pressurized gas from the pressure application section 44 beyond the fixing edge to the free end 44'. The intermediate sealing layer, which is close to the outer layer, also helps to prevent leakage of pressurized gas from inside the belt to the atmosphere.

Reference is now made to Figures 10 to 16, which illustrate the apparatus adapted to cooperate with the housing of the puncture unit 18 to initiate the discharge of pressurized gas from the gas cartridge 21. The discharged gas flows through the interconnecting structure 8 from the housing of the puncture unit 18 to the pressure regulating unit 24.

As shown in Figures 10 and 11, a puncture pin 19 that normally protrudes outward from the puncture unit housing 18 when in a retracted position can be subsequently displaced axially into the hole 82 formed within the puncture unit housing 18.

The puncture pin 19 is configured with an elongated shaft 87 terminating in a pointed end 88 adapted to pierce the metal cover 37 of the gas cartridge 21, after the latter has been inserted substantially as far as possible into the housing of the puncture unit 18 through an opening at one end opposite the puncture pin 19 by means of a threaded hook 36. The puncture pin 19 also has an oversized head element 89, which is made contact when a driving force is applied by means of the trigger handle and is displaced to an inwardly displaced position. Displacing the puncture pin 19 with sufficient force to the inwardly displaced position causes the pointed end 88 to pierce the metal cover 37, resulting in the discharge of pressurized gas from the gas cartridge 21. The discharged gas flows through the orifice 82 and the conduit 93, which is in fluid communication with the orifice 82 and passes through the interconnecting structure 8 from the puncture unit housing 18 to the pressure regulating unit housing 96 24. Sealing elements 22 and 23, for example O-rings, at the two ends of the orifice 82, respectively, prevent gas leakage.

The head element 89 limits the inward displacement of the puncture pin 19 by making contact with a surface of the puncture unit housing 18 when it is placed or set in the displaced position. The puncture pin 19 can return to the retracted position by the pressure of the discharged gas when the force applied to the activation handle is released.

Alternatively, as shown in Figure 12, a helical spring 20 surrounding the axis of the puncture pin is biased to assist in returning the puncture pin to the retracted position after the force applied by the trigger handle is released. The helical spring 20 can be compressed by the head element 89, for example, simultaneously with the pivoting of the trigger handle and the piercing of the metal cover. When the force applied to the trigger handle is released, the stored spring energy is also released, causing the puncture pin to retract. Consequently, the retracted head element can apply a force that causes the trigger handle to pivot in a direction opposite to its non-pivoted position.

Figure 13 illustrates a user-friendly actuation handle 3 when separated from the gas flow control assembly housing. The actuation handle 3 comprises a thin, broad, substantially flat, user-manipulating surface 101, which may have an arched distal edge to prevent interference with the housing when pivoted. The user-manipulating surface 101 is provided with two opposing side walls 103 adapted to be contiguous with a side wall of the corresponding upper housing section when the actuation handle 3 is in a non-pivoted position and extending along the entire length of the surface 101, or along only a distal portion of the surface 101 as shown in Figures 1 and 14. An arched extension 104 is located below and curves inward in a portion thereof with respect to the distal region of the corresponding side wall. A flat surface 107 substantially perpendicular to the user-manipulated surface 101 is in inward contact with respect to an extreme distal portion of a corresponding pair of a side wall 103 and an extension 104. A laterally extending bar 109 extends between the two flat surfaces 107, and has a curved surface that is rotatably mounted on two laterally spaced thin concave seats 28 provided with a lower section 38 (Figure 2), to define the axis of rotation of the trigger handle 3.

A cam 112, for example elliptical in shape, projects downwards from the bar 109 and is in actuable proximity to the head element 89 of the puncture pin, as shown in Figure 15. One or more stops 115, for example triangular in shape, project distally from the bar 109 to limit the pivoting displacement of the activation handle 3 when it comes into contact with a region of the housing of the gas flow control assembly.

This configuration of the trigger handle 3 offers a mechanical advantage in terms of the ratio between the longitudinal length L of the user-manipulated surface 101, from the line 116 passing through its axis of rotation, which coincides with the bar 109, and the longitudinal length M of the cam 112 from the axis of rotation, which ranges from 16 to 22:1, for example, 20:1. With this mechanical advantage, an average magnitude force applied when raising the surface 101 will generate an amplified driving force applied to the piercing pin on the order of 20 kg, which is sufficient to pierce the metal cover 37 of the gas cartridge 21.

When the actuating handle 3 pivots about its axis of rotation as shown in Figures 14 and 16, the cam 112 attached to it also pivots in a similar direction. In this pivoting position, the curved periphery of the cam 112 makes sliding, actuated contact with the head element 89 in the inwardly displaced position, so that the pointed end of the piercing pin pierces the metal cover. A curved recess 47 formed in the housing of the gas flow control assembly facilitates the interference-free pivoting movement of the arcuate extension 104. The actions are reversed when the actuating handle 3 is rotated in the opposite direction.

The structure and operation of the pressure regulating unit 24 will be described below, with reference to Figures 6, 7, 11 and 17 to 20.

As shown in Figure 17, the pressure regulating unit 24 has a housing 96 configured with an internal cavity within which the piston 25, equipped with an O-ring 27, or any other suitable sealing element, is axially and differentially displaceable to define a spring-based supply chamber 133 and a separate regulating chamber 134. The supply chamber 133 is supplied with atmospheric air through the opening 138 formed in the housing 96.

A narrow hollow tube 26 connected to the piston 25, such as by means of adhesive material 139, or alternatively by means of a clamping device such as a threaded connection, passes through the entire thickness of the piston 25 and is in fluid communication with the regulating chamber 134. The tube 26 is adapted to receive pressurized gas discharged from the gas cartridge through the conduit 93 and to transfer the gas to the regulating chamber 134. The helical spring 129, which may be attached to the distal edge 137 of the supply chamber 133, surrounds the tube 26 and is used to control the pressure within the belt.

The cap 30, which may be metallic and threaded onto the housing 96 at its narrow end 98, is used to direct the pressurized gas to the tube 26. A planar sealing element 31, for example made of EPDM rubber, is fixed to the proximal end of the cap 30 and is also fixed to a flanged annular element 32, for example flat, configured to carry an elongated annular element 141 into which the tube 26 can be received and axially displaced. The annular element 141 has two openings 144, which may be diametrically opposed to each other. One of the openings 144 can be aligned with the conduit 93 when the cap 30 is fully engaged with the housing 96, using alignment means well known to those skilled in the art. The discharged pressurized gas flows without escape from duct 93 to the aligned opening 144, and from there to the distal end of tube 26, i.e., near the cap 30, by means of various specific ducts, such as ducts of different diameters and orientations, arranged within the flanged annular element 32 and the elongated element 141. The proximal end of the elongated element 141 houses the O-ring 27, which constitutes an additional means of preventing the escape of the pressurized gas.

Three secondary passageways 152, 162 and 172 formed in the bushing 29, which is connected to the housing 96, are in fluid communication with the regulating chamber 134. The first passageway 152 is used for the flow of pressurized gas into the belt. The first passage 152 may be connected to a threaded receptacle or socket 154, which is adapted to be releasably coupled, for example, to the discharge conduit 114 illustrated in Figures 7 and 12. The manual pressure release initiator 4 is connected to the second passage 162. The pressurized gas, if its pressure rises to around a predetermined threshold, can be released to the atmosphere by means of the safety valve 177, the structure of which is well known to those skilled in the art, through the third passage 172. In this way, the same pneumatic tourniquet can be used to suppress or interrupt bleeding while the victim is being treated in the emergency room, transported to the hospital, and treated there without having to worry about excessive gas pressure.

When the pressurized gas is initially discharged from the gas cartridge 21, there is axial clearance between the distal end of the tube 26 and the sealing element 31 because the atmospheric pressure in the supply chamber 133 is greater than or equal to the pressure in the regulating chamber 134, which is devoid of pressurized gas, and the spring 129 is biased or polarized to retain the piston at a predetermined spacing from the distal edge 137 of the supply chamber 133. In this way, the pressurized gas is introduced into the tube 26 and flows into the regulating chamber 134 through the first passage 152, allowing the pressure inside the belt 53 to increase. Finally, as the pressurized gas flows into the regulating chamber 134, the pressure in the regulating chamber 134 becomes greater than the pressure in the supply chamber 133 and greater than the polarizing force of the spring 129, forcing the piston 25 to move distally. When the piston 25 has moved sufficiently distally, the distal end of the tube 26 is occluded by the sealing element 31, preventing further entry of pressurized gas. In this way, the pressure inside the strap 53 is maintained at a predetermined level, and sufficient pressurized gas remains in the gas cartridge 21 to allow for further hemorrhage suppression or interruption operations and to give the pneumatic tourniquet the capability of being a multi-purpose tourniquet.

Unlike prior art pressure regulators that rely on precise and expensive machining with a CNC lathe to achieve a reliable seal, to provide, for example, a tapered tube configuration with a smooth finish and having an outside diameter of at least 6 mm that is integrally formed with the piston, the tube 26 advantageously has an outside diameter 148 of less than 2.5 mm. With such a small dimension, the tube 26 shown in Figure 18 can achieve a reliable seal by providing a tapered distal end 164 produced by an economical cut and without a smooth finish, since the mere contact between the distal end and the sealing element, resulting in only a slight depression of the sealing element, is sufficient to reliably occlude the tube 26. Other advantages of a small-sized tube include the ability to be mechanically connected to the piston, a fast and economical material removal time since the tube is produced from a blank having a diameter substantially equal to that of the tube instead of the relatively large integral piston as practiced in the prior art, a simple seal produced, and a low sealing force required in response to the use of a small-diameter tube.

The operation of the manual pressure release initiator 4 will now be described with reference to Figures 6, 12, 17, 19 and 20.

The manual pressure release initiator 4 comprises a main rod 166 that is axially displaceable within the second passage 162 of the bushing 29 and cooperates with an O-ring 167 normally fitted within the second passage and having an outside diameter substantially equal to it. A secondary rod 173 extends proximally from, and below, the proximal end of the main rod 166 and terminates in a finger-engaging protrusion 176. A stop 178, for example an oblique stop, extends proximally from the interface between the main rod 166 and the secondary rod 173 and is used to limit the proximal displacement of the manual pressure release initiator 4 by contacting a housing element 33, as shown in Figure 7.

Alternatively, the manual pressure release initiator may comprise a single rod extending distally from protrusion 176.

Figures 12 and 19 illustrate the manual pressure release initiator 4 when placed in a retracted proximal position. In this retracted position, the main rod 166 is received within, and coupled with, the O-ring 167, which is hermetically coupled within the second passage 162, so that the second passage is simultaneously occluded by the main rod 166 and the O-ring 167 to prevent the escape of the pressurized fluid received in the regulating chamber 134 to the atmosphere.

If the physician wishes to reduce the pressure inside the strap to remove the tourniquet from the victim or to prevent the development of ischemia within the muscle tissues during prolonged use of the tourniquet, the protrusion 176 is pushed to cause distal displacement of the main rod 166<along with the o-ring>167<attached to it. When the main rod 166 is placed in the advanced/distal position illustrated in Figure 20, the O-ring 167 moves outward from the second passage 162 and into the regulating chamber 134, creating a radial clearance between the main rod 166 and the wall of the second passage 162. When the main rod 166 is advanced distally to its maximum extension, it contacts the piston 25 and causes the distal end of the tube 26 to be occluded by the sealing element 31. Since the distal end of the tube 26 is occluded, the entry of pressurized gas into the regulating chamber 134 is prevented, and the fluid received in the regulating chamber 134 begins to escape to the atmosphere through the radial clearance around the main rod 166, thus reducing the magnitude of the hemorrhage suppression or interruption force applied by the fluid pressure inside the belt. The magnitude of the hemorrhage-suppressing force can be reduced periodically for short intervals of, for example, 10 to 15 minutes.

The degree of pressure reduction can be controlled simply by releasing the force applied to the protrusion 176. After the force applied to the protrusion 176 is released, the pressurized gas remaining inside the belt flows through the first passage 152 and causes the piston 25 to remain distally advanced. Finally, the main rod 166 separates from the piston 25 and subsequently moves proximally within the second passage 162. The main rod 166 carries the O-ring 167 and causes the latter to be received again within the second passage 162 to occlude the radial play.

If all the pressurized gas is allowed to escape to the atmosphere, the supply chamber 133 and the regulating chamber 134 will reach equilibrium conditions and the distal end of the tube 26 will no longer be occluded by the sealing element 141. In this way, an additional quantity of pressurized gas will be supplied to the regulating chamber 134.

The previously unknown ability to periodically deflate the inside of a tourniquet in a prehospital setting offers significant clinical advantages by preventing ischemia despite prolonged use. The physician accompanying the injured person to the hospital can monitor their physiological condition to prevent complications such as metabolic changes, reperfusion syndrome, and cardiac arrest.

Furthermore, when the protrusion 176 is secured to the distal advanced position by means of a locking device movably connected to the housing of the gas flow control assembly, the distal end of the tube 26 will remain occluded indefinitely, allowing the pressurized gas remaining in the gas cartridge to be used for further hemorrhage suppression or interruption operations with respect to other wound victims, after the inflatable strap has been replaced.

Figures 21 and 22 illustrate another embodiment of a pneumatic tourniquet 240 that can be compactly stored by means of a plurality of spaced prongs 276 extending laterally from the gas flow control assembly 243. The prongs 276 can be inserted into and connected to the socket 277 provided with the housing element 210 of the non-pivoting constriction device 248. The receptacle or socket 277 is sized to allow connection with the prongs 276, but permits feeding of the inflatable belt 43 from below along the belt-attachable surface of the rocker arm 211. The prongs 276 are pressed together to release the gas flow control assembly 243 from the constriction device 248. The operation of the gas flow control assembly 243 and the constriction device 248 is identical to that of the gas flow control assembly of gas 43 and the constriction device 48, respectively, of Figure 1.

Figure 23 illustrates another embodiment of a pneumatic tourniquet 340 comprising a constricting device 248 as described in Figure 22 and a gas flow control assembly 343 lacking a pressure regulating unit for a more compact configuration. The gas flow control assembly 343 comprises the same activation handle 3 for initiating inflation of the strap 49, a puncture unit housing 18 into which the gas cartridge 21 can be releasably coupled, and a puncture pin 19 for piercing the metal cover that normally seals the gas cartridge, as described above with respect to Figures 11 and 13. The connection section 46 shown in Figure 7 can be used to attach the strap 49 to the housing of the gas flow control assembly. The pressurized gas flow discharged from the gas cartridge can be directed to an internal chamber in fluid communication with a safety valve 177 shown in Figure 17 before flowing into the inflatable belt to prevent excessively high pressures from occurring.

A plurality of spaced prongs 276 (Figure 22) extending laterally from the gas flow control assembly 343 can be inserted into, and connected to, the receptacle or socket 277 provided with the housing member 210 of the constricting device 248 to achieve compact storage. The prongs 276 are pressed together to release the gas flow control assembly 343 from the constricting device 248.

Another embodiment of a 440 pneumatic turnstile is illustrated in Figures 24 to 30.

As shown in Figure 24, the pneumatic tourniquet 440 comprises a gas flow control assembly 443 provided with an easy-to-use activation handle 447, a non-pivoting constriction device 448 connectable to the gas flow control assembly 443, for example as shown in Figure 23 to provide a compact housing without a pressure regulator, and an inflatable strap 449 that is connected to the gas flow control assembly 443 and selectively clamped by the constriction device 448. In this embodiment, the inflatable strap 449 is configured without an internal sealing layer; however, the passage of pressurized gas from a fixing edge associated with the constriction device 448 to the free end of the strap is prevented by an external sealing element, as will be described later.

It will be appreciated that the inflatable strap 449 can also be configured with an internal sealing layer and that the pneumatic tourniquet 440 can be configured with a pressure regulator.

Figure 25 illustrates another embodiment of a gas flow control assembly. The gas flow control assembly 443 is shown to be supported by the constricting device 448 when the activation handle is withdrawn. The gas cartridge 461, which is equipped with a valve actuator for initiating gas discharge, is shown to be releasably coupled, for example, by a threaded connection within a piston housing 468, for example, made of two sections of different sizes, 468a and 468b. An elongated activation piston 472, in its non-activated position, protrudes through an opening in the piston housing section 468a, such that its head or head 474 is separated from a laterally extending shaft 476 (Figure 29), i.e., relative to the longitudinal axis of the gas cartridge 461, around which the activation handle can rotate. After activation, the activation piston 472 returns to the non-activated position by means of spring 471.

The gas flow control assembly 443 may also include means for adjusting the gas pressure within the inner belt. A pressure release valve 477 for manually releasing the pressure in the inner belt, for example, by a slow and controlled release of pressure before removing the belt from the subject, may be operatively connected to the piston housing section 468a. A pressure control mechanism 478 for automatically regulating the pressure in the inner belt during deployment of the pneumatic tourniquet may be operatively connected to the piston housing section 468a via a conduit. The pressure control mechanism 478 may have a selector 479 by means of which a user can select the pressure to be set.

As shown in Figure 26, the inflatable strap 449, which has two different widths, can be configured with a plurality of cells interconnected in series, such as cells 456 to 458, adapted to help reduce the volume inside the strap that can be inflated. This reduces the volume of pressurized gas required, relative to a pneumatic strap lacking cells interconnected in series, to transmit sufficient hemorrhage suppression or interruption force to the injured limb. Each of the cells 456 to 458 is attached to an outer rim layer 451 that extends longitudinally from the strap 449.

A plurality of identical, series-interconnected cells 458 may be provided in the narrow-width section 459. Cell 456 is arranged in the wide-width connecting section 452, and the transition cell 457, which has a change in width, is interposed between cell 452 and cell 458, which is closest to cell 456. A short, longitudinally extended neck portion 431 extends between two adjacent cells to facilitate the flow of pressurized gas between them. Two widthwise protrusions 434a and 434b, for example tooth-shaped, extend from opposite sides of corresponding regions of the border layer 451 to delimit the corresponding neck portion 431 and adjacent, generally curved, surfaces of the adjacent cells. The inlet port 437 through which pressurized gas flows into the belt projects inward through the top wall of cell 456, and the fastening means 439 surrounding the inlet port 437 for connection to the housing of the gas flow control assembly project upward from cell 456. Each fastening means 439 may be a snap-on or pressure-fit fastening device or other connecting means well known to those skilled in the art, whether releasable or inseparable, and may be spaced from the inlet port 437 by a different distance. Alternatively, all the fastening means may be spaced equidistantly from the inlet port 437.

Figures 27A-B illustrate top and side views, respectively, of the strap 449 when inflated and disconnected from the gas flow control assembly. In addition to the wide-width cell 456 and the transition cell 457, the strap 449 is configured with a plurality of narrow-width cells 458a-e. Through the adjacent neck portion 431 of each cell, pressurized gas can flow from the inlet port 437 to inflate the strap 449. A partition 467 joining cell 458e and the terminal cell 462 prevents the flow of pressurized gas to the terminal cell 462, ensuring that the deflated terminal cell 462 will have a minimum thickness to be comfortable for the subject when the remaining portions of the strap 449 are wrapped around a limb of the subject and inflated. Of course, the additional portions of the inflated strap 449 adjacent to the terminal cell 462 that protrude distally from the attachment edge of the constriction device may deflate when the attachment edge prevents pressurized gas from flowing into these additional portions.

Each cell is bounded by the outer surface 453 and the end-facing surface 454 of the strap 449 and by the cross-protrusions 434 embedded in each of the outer surface 453 and the end-facing surface 454. When the strap 449 is inflated, the cross-protrusion on the outer surface 453 separates from the corresponding cross-protrusion on the end-facing surface 454 to form a pyramidal protrusion 434'. The apex of the pyramidal protrusion 434' projecting from the side of the outer surface 453 meets the apex of a corresponding pyramidal protrusion 434' projecting from the side of the limb-facing surface 454 at the longitudinally extending weld line 481, which is the connection interface between the outer surface 453 and the limb-facing surface 454.

Figure 27C illustrates the belt 449 when the wide-width cell 456 is connected to the gas flow control assembly 443 and the free end 462 of the belt is pre-feeding through the constriction device 448. A screw 441 is shown passing through an opening 501 formed in the coupling plate 506 of the lower housing 538 (Figure 33), and is engaged with corresponding fastening means. A screw 441 can also pass through an opening formed in the lower surface 41 of Figure 4 to be engaged with corresponding fastening means. The plurality of narrow-width cells 458 extend circumferentially to the constriction device 448.

Figure 28A illustrates a cross-sectional view of the connection section 452. The flexible inlet port 437 protrudes through the outer layer 453 of the inflatable belt, and its central passageway 438 is in fluid communication with the belt interior 465, which is located between the outer layer 453 and the end-contact layer 454 of the inflatable belt. To reduce stress concentrations on the connection section 452, a semi-rigid sealing layer 424, for example made of polyurethane, thermoplastic polyurethane (TPU), or similar materials, is attached with an opening to both the inlet port 437 and the outer belt layer 453, for example, by high-frequency welding. The thickness of the semi-rigid sealing layer 424 can vary between 0.1 and 0.5 mm, for example, 0.2 mm. With the exception of the opening provided to accommodate the inlet port, the semi-rigid sealing layer 424 has no holes. The inlet port 437 also protrudes through a rigid plastic plate 427, which is also fixed to the semi-rigid layer 424, for example made of HDPE and polypropylene, from which a plurality of fastening means, for example fastening means 439a-b, protrude.

For example, as shown in Figures 28B-D, the inlet port 437 is configured with a mounting element 435 for coupling to the semi-rigid layer 424. The rigid plate 427 is configured with an opening 426 to receive the inlet port 437 and with four protrusions 428, each of which can be connected with a fastening device, for example a screw, passing through a corresponding hole formed in a coupling plate of the gas flow control assembly housing. The outer belt layer 453, in turn, is formed with four openings 463 to accommodate the protrusions 428, respectively, and with a central opening 466 to accommodate the inlet port 437. After assembly, the connection section 452 appears as shown in Figure 26.

Prior art methods for connecting an inflatable strap to a gas flow control assembly typically include a single threaded connection with a valve core. This single connection produces a relatively high stress concentration during deployment of the pneumatic tourniquet as the strap, inflated to a relatively high pressure, wraps around an injured limb and applies a relatively high tensile force to the single threaded connection. Often, pores or small perforations develop in the strap due to the high stress concentration, resulting in a reduction of the strap's internal pressure and a waste of pressurized gas. The development of a high stress concentration at the inflated strap connection is exacerbated when the pneumatic tourniquet provides additional features found in the present invention, such as the pivoting activation handle, the constriction device, the safety release valve, and the self-regulating pressure control mechanism, which, when operated, generate vibratory forces that add to the stress concentration.

The relatively high stress concentration is advantageously reduced by the use of the connection section 452, whereby the inflatable belt is connected to the gas flow control assembly housing by a plurality of connections, rather than a single connection. The inlet port 437 is coupled, for example, releasably coupled, to a nozzle 511 that protrudes from the rigid coupling plate 506 (Figure 33) of the gas flow control assembly housing and is part of the piston housing 468 (Figure 27C), or is otherwise accessible to the coupling plate, and the coupling plate is further securely fastened to the connection section 452 by the plurality of fastening means. When the belt is inflated, the inlet port 437 is pressed against the coupling plate 506 and the additional pressurized gas can flow freely from the gas cartridge into the inside of the belt 465. The semi-rigid sealing layer 424 provides additional protection against discharge of pressurized gas from the connection section 452.

Figure 29 illustrates the gas flow control assembly 443 when the actuation handle 447 is configured in a pivoting position. Two elongated, narrow, laterally spaced mounting elements 482, substantially perpendicular to a substantially flat, user-manipulated surface 491, are rotatably mounted on the shaft 476 to facilitate the pivoting movement of the actuation handle 447. The end of one of the mounting elements 482 is shown to be in force transmission relationship with the head or cap of the actuation piston 474.

Figures 30 to 31 illustrate the operation of the actuating piston 472, which functions as a force transmission element when it cooperates with the actuating handle 447. The actuating piston 472 is guided longitudinally within a longitudinal groove formed in the piston housing 468 (not shown). The actuating piston 472 carries an angled channel 494.

In Figure 30, the activation handle 447 is in a non-pivoted position, and the activation piston 472 is fixed in the non-activated position, while a lateral edge of a mounting element 482 is in bearing relationship with the activation piston head 474. The distal end of the activation piston 472 is slightly separated from the valve stem 464 of the gas cartridge 461, which is shown in a protruding position. In the non-activated position of the activation piston 472, the short, transversely extending portion of the conduit 494 is not aligned with a conduit 497 fixed to a discharge port 469 of the piston housing 468 and extending through the inlet port of the inflatable belt 449, only a portion of which is illustrated, to prevent inflation of the belt due to leakage of the pressurized gas. Leakage of pressurized gas from the gas cartridge 461 is also prevented by the O-ring 496, which is fixed to the base of the valve stem 464, even during periods of non-use. The conduit 497 is separated from the actuating piston 472 by a very small gap.

In Figure 31, the actuating handle 447 pivots and transmits the actuating force to the actuating piston 472 via the head 474, while the spring 471, attached to a recessed portion of the piston housing, is compressed. The actuating piston 472 moves longitudinally until the short portion of the transversely extending conduit 494 is aligned with conduit 497. The valve stem 464 is contacted by the actuating piston 472 and retracts, exposing the valve seat and allowing pressurized gas to flow from inside the gas cartridge 461 through the valve seat into conduit 494. Since conduit 494 is aligned with conduit 497, pressurized gas will also flow into the belt through the inlet port. A plurality of O-rings 483 surrounding the conduit 494 prevent gas leakage from the support region between conduit 494 and conduit 497. In one embodiment, a visually distinct pressure gauge 513, schematically illustrated and in fluid communication with the inside of the belt, indicates when the inside of the belt is inflated. In another embodiment, the user will terminate the inflation of pressurized gas inside the belt in response to an audible feedback generated by the pressure control mechanism 478 (Figure 27C) when gas is released from there.

When the activation force is released, the force of the spring 471 surrounding the activation piston 472 is released to drive the activation handle 447 to the non-pivoted position and the conduit 494 to become misaligned with the conduit 497, as shown in Figure 30. In addition, the spring surrounding the valve stem 464 is no longer compressed and the valve stem returns to the extended position.

Alternatively, the actuating piston 472 can be driven longitudinally by means of a button 541, or any other actuator, protruding from the lower housing 538 of the gas flow control assembly 443, as shown in Figure 27C. When the actuating force is transmitted, a movable rod 543 connected to, or in force-transmission relationship with, the button 541 is driven longitudinally to proximally displace the head of the actuating piston 474. The operation of the actuating piston is as described above.

It will be noted that the activation piston 472 can be used to actuate the puncture pin 19 shown in Figure 11.

The pressurized gas discharged from the gas cartridge 461 after the transmission of the activation force can be in fluid communication with the pressure release valve 477 and the pressure control mechanism 478 by means of corresponding conduits also fixed to the piston housing 468.

The conduit 494, carried by the actuating piston 472, can be configured with additional angled portions, each of which can be aligned with a corresponding conduit in a manner similar to that shown in Figure 31 after the transmission of the actuating force. To provide the desired pressure control function, each of the corresponding conduits can be equipped with a pressure biasing or polarizing valve or other mechanism and, optionally, with a sealing element.

Reference is now made to Figure 32A, which illustrates a cross-sectional view of a portion of the constricting device 448A. The housing member 510 and the rocker arm 521 are configured similarly to, and have a similar function to, their counterparts in Figure 9, with the exception of the addition of the sealing element 533. The distance from the axis 12, through which the rocker arm 521 can pivot to the proximal leg 534, is significantly shorter than the distance to the distal leg 536. The distal leg 536 can be significantly longer than the proximal leg 534. Furthermore, the side walls 514 of the housing member 510 are formed with a thin intermediate space, within which the longitudinally extending external sealing element 533 is secured. The external sealing element 533 is also shown in Figures 32B and 33. When the rocker arm 521 rotates in response to contact with the injured limb and a tensile force applied to the inflatable strap 449, as shown in Figure 32B, a clamping force is applied to the strap. The external sealing element 533, located at the clamping edge and preferably semi-rigid, for example with a Shore hardness of 70, complements the clamping force to prevent pressurized gas from flowing to the free end of the strap 449. This deflates the free end of the strap, making it more comfortable for the patient and less likely to cause puncture.

Figure 34 illustrates a constriction device 448B configured with an external sealing element 537 attached to the proximal leg 534 of the rocker arm.

Figure 35 illustrates a constriction device 448C configured with an external sealing element 533 and an external sealing element 537.

The tourniquet in Figure 32B, for example, is well suited for combat implementations and for a small-sized tourniquet that can be compactly stored in a soldier's backpack or other storage equipment.

The following are some of the advantageous features of such a small tourniquet:

i. Small gas cartridge: The gas cartridge has a volume ranging from 3 to 7 ml, smaller than the standard 7 ml volume. The relatively small gas cartridge is fully insertable within the gas flow control assembly without protruding outwards, preventing damage to the gas cartridge if it is accidentally disconnected from the gas flow control assembly—a significant advantage in terms of reliability and safety.

ii. Environmental adaptability: The use of a noble gas, such as nitrogen or argon, or a refrigerant gas, which is stored in the gas cartridge in a gaseous state without risk of freezing, allows the pneumatic turnstile to operate in a wide temperature range of -40 °C to 70 °C. The turnstile can also be used in different environments, such as on land, in the air, or underwater, as it is not affected by atmospheric pressure.

iii. Activation: The actuator, whether the handle or the activation button, has sufficient structural strength to transmit a high-magnitude activation force that causes the pressurized gas to be discharged from the gas cartridge. The design of the activation handle facilitates simple and intuitive operation, and consequently, the suppression or interruption of bleeding can be achieved in just a few seconds.

iv. Inflatable strap with two widths and interconnected cells: The unique configuration of this strap has a narrower width and smaller internal volume than inflatable straps of the prior art. The wide section allows for a reduction in the force required to achieve hemorrhage suppression or interruption, and the narrow section, configured with interconnected cells, allows for the use of a smaller volume of pressurized gas compared to an inflatable strap without interconnected cells. The strap can be applied to very small, uninjured limbs, due to the wide section which will compress the limb when inflated, as well as to very large limbs, for example, those with a circumference of 85 cm, due to the long, narrow section.

v. Automatic pressure relief valve: It is not necessary to use the entire volume of pressurized gas held in the gas cartridge when the belt is inflated to a preset constant pressure. When a predetermined high pressure is reached inside the belt, the pressure relief valve will release some of the gas from inside the belt to the atmosphere to ensure that the pressure inside the belt is reduced to the preset pressure. In some embodiments, the pressure relief valve generates an audible feedback, such as a whistle, to indicate to the user when to stop inflating the belt.

vi. Gas flow control assembly and buckle connection constriction device: The prongs extending laterally from the gas flow control assembly and insertable into the socket of the non-pivoting constriction device facilitate a simple and intuitive connection that is resistant to high pressures and prevents unwanted detachment.

vii. Constriction device: The constriction device allows for smooth movement of the strap and also allows for one-handed manipulation of the strap to facilitate its automatic deployment.

Although some embodiments of the invention have been described by way of illustration, it will be evident that the invention can be carried out with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the reach of persons skilled in the art, without exceeding the scope of the claims.

Claims (15)

1. A pneumatic turnstile (40), comprising an inflatable strap (49) adapted to receive pressurized gas and to be wrapped around an injured limb to provide a desired hemorrhage suppression or interruption force, wherein the strap includes an inner layer (15), an outer layer (13) and an intermediate sealing layer (14) that are interconnected; a housing (2, 38) having a puncture unit housing (18) to which a gas cartridge (21) filled with pressurized gas is attached, a puncture pin (19) terminating with a pointed end (88), and an outlet port (73); means (3) for actuated contact of the puncture pin to an inwardly displaced position in which the pointed end of the puncture pin pierces a punctureable cover (37) that normally seals the gas cartridge, causing pressurized gas to discharge from the gas cartridge and flow through the outlet port into an interior of the inflatable strap; a constriction device (48) adapted to receive a free end (44') of said strap (49) such that said free end can be moved without restriction within said constriction device until it is secured by it when said strap is sufficiently taut to transmit the force of suppressing or interrupting bleeding; wherein the constricting device comprises a housing member (10) and a rocker arm (11) rotatably mounted on and within said housing member by means of a longitudinally extending shaft (12), the rocker arm being configured to move angularly about the shaft until a flat surface (71) of the rocker arm is established in a clamping relationship with a clamping edge (66) of the housing member while the strap is interposed between the flat surface and the clamping edge, in response to a force applied by the injured limb on the rocker arm when the strap is sufficiently taut, wherein a clamping force applied by the rocker surface and the clamping edge on the sealing element prevents the flow of pressurized gas from a pressure-applying section (44) of the strap that is wrapped around the injured limb to said free end of the strap, causing the free end to be considerably thinner than the pressure-applying section. 2. The pneumatic tourniquet (40) according to claim 1, wherein the inflatable strap (49) includes a connection section (46) having a different width than the pressure application section (44). 3. The pneumatic tourniquet (40) according to claim 2, wherein the connection section (46) and the pressure application section (44) are made of different materials having a different degree of flexibility. 4. The pneumatic tourniquet (40) according to claim 2, wherein the connection section (46) includes an internal coupling plate (61) between the outer layer (13) and the intermediate sealing layer (14) of the inflatable strap (49). 5. The pneumatic tourniquet (40) according to claim 4, wherein the outlet port (73) is secured to the inner fixing plate (61) through an opening formed in the inner coupling plate and in the outer layer (13) and the intermediate sealing layer (14) of the inflatable strap (49). 6. The pneumatic tourniquet (40) according to claim 1, wherein the means (3) that actuate the puncture pin includes an activation handle. 7. The pneumatic tourniquet (40) according to any of the preceding claims, wherein the inner layer (15) is made of a flexible, tear-resistant material. 8. The pneumatic tourniquet (40) according to any of the preceding claims, wherein the outer layer (13) is made of a flexible, puncture-resistant material. 9. The pneumatic tourniquet (40) according to claim 8, wherein the puncture-resistant material includes a material selected from the group consisting of silicone elastomer and a fabric of a flexible material. 10. The pneumatic tourniquet (40) according to claim 9, wherein the flexible material is selected from the group consisting of nylon and polyester. 11. The pneumatic tourniquet (40) according to any of the preceding claims, wherein the outer layer (13) is sealed with a puncture-resistant layer of material. 12. The pneumatic tourniquet (40) according to claim 11, wherein the puncture-resistant material layer is polyurethane. 13. The pneumatic tourniquet (40) according to any of the preceding claims, wherein the intermediate layer (14) is made of a sealing material. 14. The pneumatic turnstile (40) according to claim 13, wherein the sealing material is polyurethane. 15. The pneumatic turnstile (40) according to any of the preceding claims, wherein the inner layer (15), the outer layer (13) and the intermediate sealing layer (14) have substantially equal lengths and widths.